This kind of optical recording/reproducing apparatus optically writes information on or optically readouts information from an optical disk such as MD (a mini disc), a magneto-optical disk, or the like while driving an objective lens in two axial directions, namely an optical axial direction (a focusing direction) perpendicular to a recording surface of the optical disk and a radial direction parallel to the recording surface, to compensate shifts in focusing due to wobbling of the optical disk or in tracking due to deviation or the like of the optical disk.
Recently, in an optical recording/reproducing apparatus provided with an objective-lens actuator for driving an objective lens in a focusing direction and in a radial direction via a plurality of elastic members arranged almost in parallel to one another, a configuration in which a fixing member for attaching the elastic members is positioned between the objective lens and a light source to reduce the size of the whole apparatus mainly has been employed.
An example of the above-mentioned conventional optical recording/reproducing apparatus will be described with reference to the drawings as follows.
FIG. 6 is a plan view showing a conventional optical recording/reproducing apparatus. FIG. 7 is a sectional side view showing the conventional optical recording/reproducing apparatus.
As shown in FIGS. 6 and 7, the conventional optical recording/reproducing apparatus comprises: a light receiving and emitting device 61 including a light source for emitting divergent optical beams 63, a focusing-error-signal detector, a tracking-error-signal detector, and an information-signal detector; a collimator lens 60 for converting the divergent optical beams 63 emitted from the light source in the device 61 into parallel beams; a mirror 59 for orthogonally refracting the optical beams 63 converted to the parallel beams by the collimator lens 60; an objective lens 51 for converging the orthogonally refracted optical beams 63 onto a disk 64; an objective-lens actuator for driving the objective lens 51 in a focusing direction F and in a radial direction R of the disk 64; and an optical block 62 for fixing the device 61, the mirror 59, and the objective-lens actuator. A movable part comprising a lens holder 52 for holding the objective-lens 51, a focusing coil 54, and a pair of tracking coils 55 in the objective-lens actuator is attached to a fixing member 57 via four suspensions 56 of elastic members that are arranged in parallel to one another and that are formed of stainless steel, phosphor bronze, beryllium copper, or the like. The fixing member 57 is fixed to a base 58 that is further fixed to the optical block 62. In this case, the fixing member 57 is provided with an opening portion 57a for avoiding the interference with the optical beams 63. The fixing member 57 is positioned between the objective lens 51 and the device 61 with respect to a tangential direction T (the direction perpendicular to the focusing direction F and the radial direction R), thus reducing the size of the optical recording/reproducing apparatus in the tangential direction T. A magnetic circuit is formed of the base 58 and a pair of magnets 53, and the focusing coil 54 and the tracking coil 55 are positioned in a space within the magnetic circuit. Thus, a magnetic field is applied to the focusing coil 54 and the tracking coil 55.
The operation of the optical recording/reproducing apparatus formed as described above will be described as follows.
The divergent optical beams 63 emitted from the light source in the device 61 are converted into parallel beams by the collimator lens 60. The parallel beams are reflected by the mirror 59 and enter into the objective lens 51, thus being converged on the disk 64. Light reflected from the disk 64 is converged in the signal detectors on the device 61 through the reverse path, thus detecting signals. In this case, the objective lens 51 is driven by the focusing coil 54 and the tracking coil 55 in the focusing direction F and in the radial direction R respectively so as to follow wobbling or deviation of the disk 64.
In further reducing the size of the optical recording/reproducing apparatus having such a configuration as mentioned above, there are two problems of the interference between the optical beams 63 (parallel beams) that came out from the collimator lens 60 and the fixing member 57 by which the objective-lens actuator is fixed with respect to the radial direction R and the interference between the collimator lens 60 and the fixing member 57 with respect to the tangential direction T.
With the reduction in size of the optical recording/reproducing apparatus, the length of the suspensions 56 for supporting the movable part also is shortened and sufficient strength against disturbance vibration or impact caused when the optical recording/reproducing apparatus is dropped cannot be obtained. Thus, there is a fear of causing deformation or breakage of the suspensions 56.